1. Field of the Invention
The present invention relates generally to computer networks and more specifically relates to a method and apparatus for continuous operation of a point-of-sale system during the occurrence of a single point-of-failure.
2. Description of the Related Art
Reliability is paramount in computer network systems, such as point-of-sale systems, which are commonly used in retail sale operations. A primary source of network failure is cable breakage or faulty contacts associated with connectors. FIG. 1 shows a conventional computer network system, in which a server 10 preferably communicates through an Ethernet hub 12 and a control unit or controller 14 to each of a plurality of workstations 16A-16C. The control unit 14 preferably communicates with the workstations through a transmit path 22 and a receive path 24. In a point-of-sale system, the workstations 16A-16C are coupled to a monitor 18 and a keyboard or bump bar 20.
Data is transmitted from the server 10 to the Ethernet hub 12 and then to the control unit 14, which outputs the data on the transmit path 22. The transmit path 22 serially connects each of the plurality of workstations 16A-16C in a daisy-chain configuration. Likewise, data is transmitted from one or more of the plurality of workstations 16A-16C on the receive path 24, which connects the plurality of workstations 16A-16C to the control unit 14. The control unit 14 outputs data received from the workstations 16A-16C to the server 10 through the Ethernet hub 12.
If there is a break in the transmit path 22, at for instance point A, workstation 16C, which is located beyond the break, will not receive information from the control unit 14. Likewise, if there is a break in the receive path 24, at for instance point B, neither the control unit 14 nor the server 10 will receive information from workstations 16A-16C. Malfunctions in the server 10, control unit 14, and Ethernet link would likely result in even more catastrophic communication failures.
Accordingly, it is a goal of the method and system in accordance with the present invention to provide uninterrupted access to all workstations in a point-of-sale system despite the occurrence of a single point-of-failure in the network or malfunctions in the server, control unit, and Ethernet link.